Description

The metadata block is a section of a user script that describes the script.
It usually contains the script name, namespace, description, and include and exclude rules.
The metadata block appears in JavaScript line comments and may appear anywhere in the top level Greasemonkey code scope of the script, but is usually near the top of the file.

If the metadata block includes a key that Greasemonkey does not understand, it will be ignored.

Syntax

The metadata block must follow the format:

// ==UserScript==
// @key value
// ==/UserScript==

It must use line comments (//) like above, not block comments (/* */).
Note that the opening // ==UserScript== and closing // ==/UserScript== must be precisely at the beginning of its line.
Some keys may have multiple values.
In all cases the key and value(s) are separated by whitespace.
The closing ==/UserScript== line should be at the end of the metadata block (not at the end of the script).

@description

Example:

// @description This script even does the laundry!

Just a brief summary of what the script does, presented to the user as the script is installed, and in the manage dialog.

As of Greasemonkey 2.2: can be localized for multiple languages; see the #@name documentation for more detail.

@exclude

@grant

@icon

Example:

// @icon http://www.example.org/icon.png

The icon is, as of Greasemonkey 0.9.0, displayed in the script management interface.
Almost any image will work, but a 32x32 pixel size is best.
This value may be specified relative to the URL the script itself is downloaded from.

Add a colon and the locale code, which is the ISO 639 language code and optionally a hyphen and ISO 3166 country code, when disambiguation is necessary.
When the user's browser is configured with the matching primary language, that value will be displayed instead.

@namespace

Example:

// @namespace http://www.example.com/gmscripts

The combination of namespace and name is the unique identifier for a Greasemonkey script.
If a script is being installed, and a script with that same name and namespace already exists, it will be replaced by the new script.
Otherwise, the new script is added to the set of installed scripts.
A script author will usually put all of their scripts under one common namespace, and then assign each script a unique name.

While the namespace is non-semantic, a URL is often used.
Some authors use the common home page for the collection of scripts they have written.
But remember, the namespace can be any unique value.

@noframes

Example:

// @noframes

When present, this imperative restricts the execution of the script.
The script will run only in the top-level document, never in nested frames.
It takes no arguments, it is either present or not present.
This is off (scripts run in frames) by default.

@require

Example:

// @require http://www.example.com/example.js

There can be any number of @require keys in a script.
Each @require is downloaded once, when the script is installed, and stored on the user's hard drive alongside the script.
The URL specified may be relative to the URL the script is being installed from.

Note that since Greasemonkey 0.9.0, if Greasemonkey detects that the @require value(s) have been altered, these new values will be used (thus each @require shall be re-downloaded).

@resource

While the resourceName is non-semantic, it should comply with JavaScript identifier restrictions.
Each @resource must have a unique name.

Each @resource is downloaded once, when the script is installed, and stored on the user's hard drive alongside the script.
The URL specified may be relative to the URL the script is being installed from.

@run-at

The default if no value is provided. The script will run after the main page is loaded, but before other resources (images, style sheets, etc.) have loaded. The only guaranteed working value in Greasemonkey 4.x.

document-start

The script will run before any document begins loading, thus before any scripts run or images load.

document-idle

The script will run after the page and all resources (images, style sheets, etc.) are loaded and page scripts have run.

To detect if you are running at document-start time, check the value of document.readyState.
For example:

Adding Resources

Two metadata imperatives allow downloading files (once, at install time) for efficient reference:
First @require, which includes a remote code resource.
Second @resource, which makes a remote data resource available.

It is possible to add a new entry for either of these values, while editing a script that is already installed.
In either case, simply add the appropriate line and the referenced file will be downloaded and made available the next time the script runs.
If you specify a relative URL, then it will be interpreted as relative to the the URL the script was originally downloaded from.